• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.5
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• pp.255-260
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• 1993

The behavior of pure silt was investigated by using an automated triaxial testing device. The stress-strain behavior of silt due to the volume deformation tendency was compared with the behavior of clay prior to failure and behavior at failure under monotonic undrained compression and extension conditions. A pure silica flour was chosen to form samples. The isotropically normally-consolidated samples with 450 kPa of effective mean confining pressure and overconsolidated samples through unloading were tested. Based on the experimental results, it was qualitatively identified that the undrained strength of normally-consolidated silt increases due to its dilatant nature which is not seen in clay. Also the overconsolidated silt shows a significantly different behavior under the monotonic loadings due to the volume deformation tendency.

• Geotechnical Engineering
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• v.9 no.4
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• pp.27-36
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• 1993

The drained and undrained behavior of pure silt was investigated experimentally. Special attention was given to the stress-strain behavior of silt prior to failure and behavior at failure under monotonic and cyclic loading. A pure silica flour was chosen to form samples with two different densities of D,=80%, eo=0.68 and D,=35%, eo=0.9. The isotropically consolidated samples were tested in the triaxial testing device under monotonic undrained, drained compression and extension conditions. Also samples were tested under cyclic undrained condition. Based on the experimental results. it was qualitively identified that the overall behavior of silt is similar to that of sand. When compared with clay, silt shows a significantly different behavior due to its dilatant nature under both the monotonic and cyclic shear loadings.

• Journal of the Korean Geotechnical Society
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• v.24 no.2
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• pp.5-14
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• 2008

Shear characteristics of quarry blasted rocks were compared using large scale direct shear tests and triaxial tests. For comparison purpose, similar test conditions were simulated as much as possible and three types of relative density (50%, 70%, 90%) were employed for the test. Results indicate that stress-strain behavior shows the same trend for two tests, but the measured shear strengths differ for the different test ms and depends on the relative density. At low relative density, the internal friction angles from direct shear test are smaller than those from triaxial tests. However, at high relative density, this phenomenon is reversed.

• Journal of the Korean Society for Railway
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• v.8 no.4
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• pp.372-378
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• 2005

화강풍화토의 강도와 변형특성을 조사하기 위하여 불포화배수 삼축압축시험을 실시하였다. 주응력방향과 다짐방향을 0, 45, 90도의 세가지 방향성을 갖도록 하였다. 등방압축시 발생하는 압축변형률은 다짐각도에 따라 크게 영향을 받는다. 이차압축시의 변형거동에 관한 시간의존성은 다짐각도와 관계가 없는 것으로 판단되었다. 다짐각도가 압축강도와 변형에 미치는 영향은 특히 낮은 구속압력시에 크다. 다짐각도가 다르다 하더라도 다일러턴시 비율은 다일러턴시로 인한 강도증가와 상관하여 변화한다. 따라서 다짐풍화토는 초기 비등방성 조직을 갖고 있는 모래와 같이 비등방성 역학적 성질을 갖는다고 할 수 있다.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1061-1069
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• 2005

다짐화강풍화토의 강도와 변형특성을 조사하기 위하여 불포화배수 삼축압축실험을 실시하였다. 본 실험을 위하여 야마구치현의 시모네세키에서 화강풍화토를 구하였으며 주응력방향과 다짐방향을 0, 45, 90도의 세가지 방향성을 갖도록 하였다. 등방압축시 발생하는 압축변형률은 다짐각도에 따라 크게 영향을 받는다. 이차압축시의 변형거동에 관한 시간의존성은 다짐각도와 관계가 없다. 다짐각도가 압축강도와 변형에 미치는 영향은 특히 낮은 구속압력시에 크다. 다짐각도가 다르다 하더라도 다일러탄시 비율은 다일러턴시로 인한 강도증가와 상관하여 변화한다. 따라서 다짐풍화토는 초기 비등방성 조직을 갖고 있는 모래와 같이 비등방성 역학적 성질을 갖는다고 할 수 있다.

• Tunnel and Underground Space
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• v.23 no.5
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• pp.383-391
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• 2013

A number of true triaxial tests on rock samples have been conducted since the late 1960 and their results strongly suggest that the intermediate principal stress has a considerable effect on rock strength. Based on these experimental evidence, various 3-D rock failure criteria accounting for the effect of the intermediate principal stress have been proposed. Most of the 3-D failure criteria, however, are focused on the phenomenological description of the rock strength from the true triaxial tests, so that the associated strength parameters have little physical meaning. In order to confirm the likelihood that the intermediate principal stress dependency of rock strength is related to the presence of weak planes and their distribution to the preferred orientation, true triaxial tests are simulated with the transversely isotropic rock model. The conventional Mohr-Coulomb criterion is extended to its anisotropic version by incorporating the concept of microstructure tensor. With the anisotropic Mohr-Coulomb criterion, the critical plane approach is applied to calculate the strength of the transversely isotropic rock model and the orientation of the fracture plane. This investigation hints that the spatial distribution of microstructural planes with respect to the principal stress triad is closely related to the intermediate principal stress dependency of rock strength.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.3100-3105
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• 2010

The permanent deformation of asphalt pavement is one of the most important load-related distresses in asphalt pavement. In order to evaluate the permanent deformation, the repeated triaxial load test with different temperature and air void of hot mix asphalt was carried out. The permanent deformation prediction model has been validated by the multiple regression approach and the artificial neural networks.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.998-1003
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• 2008

It has been recognized unsaturated soil behaviour playing an important role in geomechanics. Up to now, only a few experimental data are available for the technical difficulties related to both volume changes and suction measurements. In this study, the volume changes of unsaturated compacted silty soil were monitored with proximeter (i.e. non-contactable transducer) during various triaxial compression tests, which gave a realistic estimation in the volume changes of unsaturated soil sample. Various triaxial compression tests for unsaturated soil under different drainage conditions are carried out. The behaviour of the pore pressure, namely, the pore-air pressure and the pore-water pressure, and matric suction during the shearing tests are investigated. The experimental results have revealed that the mechanical behaviour of unsaturated soil can be significantly affected by the matric suction.

• The Journal of Engineering Geology
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• v.9 no.3
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• pp.243-251
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• 1999

Granitic rock, by its nature, contains numerous micro-discontinuities including grain boundary, microcracks, microcavities and mineral cleavages. The brittle fracture of rock is a progressive procedure in which the failure occurs with prior microcracking. In this paper, initiation, propagation and interaction of microcracks are considered to be the dominant, controlling micromechanisms of macroscopic failure. The authors show a few patterns of microcrack initiation and propagation by using sequential photographs of water-saturated granite taken under triaxial compressive state. The failure process was observed directly and continuously by a newly developed triaxial compressive test system.

• Journal of the Korean Geotechnical Society
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• v.20 no.4
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• pp.5-13
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• 2004

Strength and compressibility characteristics of Light-Weighted Foam Soil (LWFS) are experimentally investigated in the paper. LWFS is composed of the dredged soils, cement and air foam to reduce unit-weight and to increase compressive strength. For these purposes, both unconfined compression tests and triaxial compression tests are carried out fer artficially prepared specimens of LWFS with various initial water contents, cement contents, mixing ratio of silty dredged soils and different confining stresses. The experimental results of LWFS indicate that the stress-strain relationship and the compressive strength are strongly influenced by cement contents rather than intial water contents of the edged soils. In this paper, the normalizing scheme considering the ratio of initial water contents, cement contents, and air foam contents has been proposed to evaluate the relationship between compressive strength of LWFS and a normalized factor.